Storage-associated shifts in the raw boar seminal microbiome at 17 °C

This study addresses the relevance of the bacterial seminal microbiome in boars, considering that bacterial compositional changes during liquid semen storage may affect sperm quality and limit the efficiency of artificial insemination. The objective was to characterize temporal changes in the seminal microbiota composition of raw boar semen incubated at 17 °C for 12 days. For this purpose, six ejaculates from Landrace boars used as artificial insemination donors were analyzed, with samples evaluated on days 1, 4, 8, and 12 through DNA extraction, amplification of the V3–V4 region of the 16S rRNA gene, and Illumina MiSeq sequencing. The results showed a progressive reduction in bacterial richness and diversity during storage, with a transition from an initially heterogeneous community, mainly represented by Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota, toward low-complexity communities relatively dominated by opportunistic taxa such as Pseudomonas, Escherichia-Shigella, Enterococcus, and Bacteroides. Overall, the study concludes that storage at 17 °C is associated with relative compositional shifts in the raw seminal microbiome toward potentially detrimental bacterial profiles, providing a baseline for understanding the dynamics of the seminal microbiota and supporting the development of more targeted and sustainable antimicrobial strategies for porcine semen preservation.